When an HTML document has been switched to designMode, its document object exposes an execCommand method to run commands that manipulate the current editable region, such as form inputs or contentEditable elements.

Most commands affect the document's selection (bold, italics, etc.), while others insert new elements (adding a link), or affect an entire line (indenting). When using contentEditable, execCommand() affects the currently active editable element.

Syntax

Return value

Note: Only returns true if part of a user interaction. Don't try using the return value to verify browser support before calling a command.

Parameters

aCommandName

A DOMString specifying the name of the command to execute. See Commands for a list of possible commands.

aShowDefaultUI

A Boolean indicating whether the default user interface should be shown. This is not implemented in Mozilla.

aValueArgument

For commands which require an input argument, is a DOMString providing that information. For example, insertImage requires the URL of the image to insert. Specify null if no argument is needed.

Commands

backColor

Changes the document background color. In styleWithCss mode, it affects the background color of the containing block instead. This requires a <color> value string to be passed in as a value argument. Note that Internet Explorer uses this to set the text background color.

bold

Toggles bold on/off for the selection or at the insertion point. Internet Explorer uses the <strong> tag instead of <b>.

ClearAuthenticationCache

Clears all authentication credentials from the cache.

contentReadOnly

Makes the content document either read-only or editable. This requires a boolean true/false as the value argument. (Not supported by Internet Explorer.)

copy

Copies the current selection to the clipboard. Conditions of having this behavior enabled vary from one browser to another, and have evolved over time. Check the compatibility table to determine if you can use it in your case.

createLink

Creates an hyperlink from the selection, but only if there is a selection. Requires a URI string as a value argument for the hyperlink's href. The URI must contain at least a single character, which may be whitespace. (Internet Explorer will create a link with a null value.)

cut

Removes the current selection and copies it to the clipboard. When this behavior is enabled varies between browsers, and its conditions have evolved over time. Check the compatibility table for usage details.

decreaseFontSize

Adds a <small> tag around the selection or at the insertion point. (Not supported by Internet Explorer.)

Enables or disables the grabber that allows absolutely-positioned elements to be moved around. This is disabled by default in Firefox 63 Beta/Dev Edition (bug 1449564)

enableInlineTableEditing

Enables or disables the table row/column insertion and deletion controls. This is disabled by default in Firefox 63 Beta/Dev Edition (bug 1449564).

enableObjectResizing

Enables or disables the resize handles on images, tables, and absolutely-positioned elements and other resizable objects. This is disabled by default in Firefox 63 Beta/Dev Edition (bug 1449564).

fontName

Changes the font name for the selection or at the insertion point. This requires a font name string (like "Arial") as a value argument.

fontSize

Changes the font size for the selection or at the insertion point. This requires an integer from 1-7 as a value argument.

foreColor

Changes a font color for the selection or at the insertion point. This requires a hexidecimal color value string as a value argument.

formatBlock

Adds an HTML block-level element around the line containing the current selection, replacing the block element containing the line if one exists (in Firefox, <blockquote> is the exception — it will wrap any containing block element). Requires a tag-name string as a value argument. Virtually all block-level elements can be used. (Internet Explorer and Edge support only heading tags H1–H6, ADDRESS, and PRE, which must be wrapped in angle brackets, such as "<H1>".)

forwardDelete

Deletes the character ahead of the cursor's position, identical to hitting the Delete key on a Windows keyboard.

heading

Adds a heading element around a selection or insertion point line. Requires the tag-name string as a value argument (i.e. "H1", "H6"). (Not supported by Internet Explorer and Safari.)

hiliteColor

Changes the background color for the selection or at the insertion point. Requires a color value string as a value argument. useCSS must be true for this to function. (Not supported by Internet Explorer.)

increaseFontSize

Adds a <big> tag around the selection or at the insertion point. (Not supported by Internet Explorer.)

indent

Indents the line containing the selection or insertion point. In Firefox, if the selection spans multiple lines at different levels of indentation, only the least indented lines in the selection will be indented.

insertBrOnReturn

Controls whether the Enter key inserts a <br> element, or splits the current block element into two. (Not supported by Internet Explorer.)

insertHorizontalRule

Inserts a <hr> element at the insertion point, or replaces the selection with it.

insertHTML

Inserts an HTML string at the insertion point (deletes selection). Requires a valid HTML string as a value argument. (Not supported by Internet Explorer.)

insertImage

Inserts an image at the insertion point (deletes selection). Requires a URL string for the image's src as a value argument. The requirements for this string are the same as createLink.